Sliding vane reversible air compressor



March 29, 1949. E. P. LARSH SLIDING VANE REVERSIBLE AIR COMPRESSOR Filed March 1, 1946 6 Sheets-Sheet l (O 4 El) m (o n x T (O S 3 v z: n 2 i m N m 5 N 8 I In f) m 2 m n 0 r In I 'I N q, s a $5 m .3 o

n O O S2 u. n D n p in INVENTOR. EVERETT P. LARSH N N 2 WM ATTO R NEY March 29, 1949. E. P. LARSH SLIDING VANE REVERSIBLE AIR COMPRESSOR Filed March 1, 1946 6 Sheets-Sheet 2 wN ON mm mm on mm mm 00 NM QN O O O NO 7 I mm mm INVENTOR.

EVERETT P. LARSH ATTORNEY March 29, 1949, R E. P. LARSH SLIDING VANE REVERSIBLE AIR COMPRESSOR 6 Sheets-Sheet 5 Filed March l, 1946 ATTORNEY March 29, 1949. I E. P. LARSH SLIDING VANE REVERSIBLE AIR COMPRESSOR 6 Sheets-Sheet 4 Filed March 1, 1946 P. LARSH EVERETT ATTORNEY March 29, 1949.

E. P. LARSH SLIDING VANE REVERSIBLE AIR COMPRESSOR 6 Sheets-Sheet 5 Filed March 1, 1946 lll llbl ll IINVENTOR. EV ER ETT P. LARSH ATTOR NEY E. P. LARSH SLIDING VANE REVERSIBLE AIR COMPRESSOR March 29, 1949.

6 Sheets-Sheet 6 Filed March 1, 1946 INVENTOR.. EVERETT P. LARSH ATTORNEY Patented Mar. 29, 1949 SLIDING vANE REVERSIBLE AIR COMPRESSOR Everett P. Larsh, Montgomery County, Ohio Application March 1, 1946, Serial No; 651,125

7 Claims.

This invention relates to rotary air compressors and the like and is designed primarily as a supercharger blower for a Diesel engine.

One object of the invention is to provide a rotary compressor of a simple construction having high efficiency.

A further object of the invention is to provide a compressor in which the fluid is supplied to and discharged from the compressor casing through separate inlet and outlet chambers.

A further object of the invention is to provide a rotary compressor in which the admission of fluid to and the discharge of the same from the compressor casing may be so controlled as to cause the compressor to function properly when the rotor rotates in either direction.

A further object of the invention is to provide a compressor of the blade type in which the radial positions of the blades are positively controlled and the outer ends of the blades are maintained in predetermined positions with relation to the compressor casing during the rotation of the rotor.

A further object of the invention is to provide a rotary compressor in which the blade controlling devices are simple in construction and freely movable.

A further object of th invention is to provide a rotary compressor of such a character that lubricant escaping from the bearing surfaces cannot enter the compressing chamber.

Other objects of the invention may appear as the compressor is described in detail.

In the accompanying drawings, Fig. 1 is a transverse section of a compressor embodying the invention, taken on the line Il of Fig. 4, showing th arrangement of the parts when th rotor rotates in a clockwise direction; Fig. 2 is a similar view showing the arrangement of parts when the rotor rotates in a counter-clockwise direction; Fig. 3 is a perspective view of a portion of the compressor casing looking in the direction of the arrows 3 on Fig. 1; Fig. 4 is a section taken on the line 4-4 of Fig. 1; Fig. 5 is a section taken on the line 5-5 of Fig. 1; Fig. 6 is a transverse section taken on the line 6-6 of Fig. 4; Fig. 7 is a detail view of one of the guide blocks; Fig. 8 is an end view of the compressor partly broken away to show the interior arrangement; Fig. 9 is a longitudinal section taken through a modified form of the invention on the line 9--9 of Fig. 10; Fig. 10 is a section taken on the line Ill-Ill of Fig. 9 looking in the direction of the arrows; Fig. 11 is a section taken on the line ll-ll of Fig. 9 looking inv the direction'of the arrows;

2 Fig. 12 is a detail view of the blade of the compressor of Fig. 9; Fig. 13 is a section of the blade taken on the line l3l3 of Fig. 12, on a larger scale; and Fig. 14 is a sectional view of the sprin connection between opposed blades.

In these drawings I have illustrated two embodiments of my invention and have shown the same as a supercharging compressor for a Diesel engine, but it is to be understood that the invention may be used for various purposes and that the compressor as a whole, as well as the several parts thereof, may take various forms without departing from the spirit of the invention.

In that embodiment shown in Figs. 1 to 8 the compressor is shown as supported in part by the rigid end wall In of the crank case of a Diesel engine to which air under pressure is to be supplied. The crank shaft ll extends through the end wall I0 and is here shown as supported in a bearing l2 mounted in that wall. The part I 3 of the crank shaft which extends outwardly beyond the wall In constitutes the shaft of the compressor. A rotor, or impeller, is mounted about the shaft l3 and comprises a cylindrical body l4 having a central bore l5 adapted to receive the shaft l3 and preferably provided with a bushing IS. The body of the rotor is connected with the shaft for rotation therewith, as by with a key l1, and is provided with a plurality of radial slots l8, in the present instance eight, and a corresponding plurality of blades l9 are slidably mounted in the respective slots.

Mounted about the shaft and enclosing the rotor is a cylindrical casing designated as a whole by the reference numeral 20. This casing may be supported in any suitabl manner but preferably it is supported directly on the shaft and held against rotation therewith. As here shown, the casing comprises end walls 2| and 22 having openings 23, eccentric to the axis of the cylinder, to receive the compressor shaft I3 and provided with bushings 24 engaging the shaft and in which the shaft rotates. Preferably the side walls have thickened portions 25 surrounding the shaft to provide adequate bearing surfaces and strength. The circumferential wall .26 of the casing is supported on the end walls 2| and 22 close to the outer edges thereof and the side walls are here shown as provided with shoulders 21 on which the circumferential wall is supported. The circumferential wall is held normally in a fixed position with relation to the end walls but it is prefer-- ably so supported that it may have a limited rotary movement with relation to the end walls for a .purpose .which will hereinafter appear.

The end walls 21 and 22 are rigidly connected one with the other by tie bolts .28 and means are provided for maintaining the peripheral portions of the end walls in such spaced relation that the circumferential wall will fit snugly between the same but may have rotary movement with relation thereto. For this purpose the end walls are provided with radial extensions, such as a series of elongate lugs 29, through which the respective bolts 28 extend and arranged between these lugs and spaced from the circumferential wall 26 is a spacing sleeve 38 through which the bolt extends and which is preferably provided at its ends with elongate lugs 31 similar to the lugs 29. Thus the bolts clamp the lugs 29 of the end walls against the lugs 3! of the spacing sleeve and the latter is of such length that the lugs 28 and therefore the end walls will be properly spaced with relation to the circumferential wall. In the present arrangement the bolt and spacing sleeve are braced by inclined rods 32 each of which is secured at its ends to, and preferably formed integral with, the sleeve 30 and the lugs 3!.

When the rotor operates at high speed the centrifugal force exerted on the blades is such that, if their radial movement is unrestrained, they have relatively large frictional contact with the inner surface of the circumferential wail 726 of the casing and both the blades and the wall are subjected to severe wear. To avoid this and to provide for a positive movement of the blades I have provided means controlled by the rotation of the rotor for positively moving the blades outwardly and for so limiting their outward movement that outer edges thereof will be maintained close to but preferably out of contact with the inner surface of the cylindrical wall throughout the rotation of the rotor. For this purpose each of the end walls of the casing is provided with an annular guideway concentric to the axis of the casing and therefore eccentric to the rotor, said guideways being here shown as inwardly facing annular channels or grooves 33. Mounted in each groove and held against radial movement therein is a series of guide members such as blocks 34 each of which is arcuate in form and fits snugly but slidably within the groove so as to be held against radial displacement with relation to the groove. Each block is provided with a bearing recess 35 and each blade has adrotates and the blocks 34 travel in the eccentric 5 grooves 33 about the axis of that rotor. The connection between the blades and the blocks being pivotal permits the blocks to adjust then.- selves with relation to the blades as they move in the grooves. The arrangement of the eccentric grooves with relation to the circumferential wall of the casing is such that the blades will be positively projected to and retained in predetermined positions with relation to that wall.

An outer housing 36 is supported about the casing in spaced relation thereto and is provided with inlet and outlet chambers through which air or other fluid is supplied to the interior of the casing. This housing may be supported in any suitable manner but in the present instance it is cylindrical in form and one end thereof is rigidly secured to the wall It of the crank case, as by welding, and the housing as a whole supported by that wall concentric with the shaft. At that end opposite the wall'lil the housing is provided with an end wall 37, here shown as dome shaped in contour. This end wall is spaced some distance from the outer end of the casing and is carried by a portion 38 of the cylindrical wall of the housing which is separate from and connected with the inner portion of the housing. In the arrangement here shown, Figs. 4 and 5, the cylindrical portion 38 extends inwardly, or rearwardly, a short distance beyond the outer end of the casing and is bent to form an annular channel 39 which overlaps th outer edge of the inner portion of the cylindricai wall. Extending radially inward from the wall 3% is an eccentric flange or wall 29 the inner edge portion of which overlaps the outer end wall of the casing. This wall ll) has a part il which extends rearwardly beneath the channel 39 and is provided with a head 42 arranged close to a bead it on the for-- ward edge of the inner part of the cylindrical Wall. The channel 39 is filled with a suitable sealing material it, such as soft rubber, in which the beads t2 and Q3 are imbedded. The rear wall of the channel 39 is partly cut away at 5 to permit it to move over the bead That portion of the flange or wall it] which overlaps the end wall of the casing is held in engagement with the latter by a clamping ring .6, and the end wall 37, including the cylindrical part 33, is removably attached to the casing by means of bolts 4'? which are secured to the outer end wall of the casing, extend through openings in the dome shaped wall 31 and are provided with thumb nuts 58 to retain the end wall 3? thereon.

The circumferential walls of the casing and of the housing are spaced radially one from the other and the space between the same is divided to form an inlet chamber and an outlet chamber both communicating with the interior of the compressor casing. In the present arrangement this space is divided by sealing members 59 and 5i of suitable sealing material, such as soft rubber, which fits tightly between the two walls and is held in place by means of an anchor bar 52 embedded in the sealing material and secured to the wall of the housing by screws 53. The sealing members are arranged on opposite sides of the casing at points where the space between the two walls is of substantially the same width on both sides of the casing. The space between the walls is thus divided into an inlet chamber 5'3 and an outlet chamber 55, both chambers being of a circumferential length slightly less than a semi-circle. The wall M which extends inwardly from the housing has an elongate opening 58 at the forward side of the inlet chamber (see Fig. l) which connects that chamber with the space between the end wall of the casing and the end wall of the housing, the latter being provided with an inlet for air, which is shown in Figs. 1 and 8 as a series of openings 63. The wall it on which the housing is mounted and which extends across the rear or inner end of the outlet chamber 55 has an opening 5! through which air under pressure is discharged from the outlet chamber. The discharged air in the present instance enters the air reservoir of the engine but it may, of course, be delivered to any suitable point of use.

The circumferential wall 25 of the casing is provided with an inlet passage leading from the inlet chamber 56 to the interior of the casing and with an outlet passage leading from the casing to the outlet chamber 51. The inlet and outlet passages may take various forms but preferably the inlet comprises a series of relatively small openings 58 distributed over approximately onehalf of that part of the circumferential wall of the casing which forms the inner wall of the in let chamber. Likewise the outlet comprises a series of relatively small openings 59 distributed over approximately one-half of that portion of the circumferential wall of the casing which forms the inner wall of the outlet chamber. As shown in Fig. 1, the inlet openings 58 are arranged at that end of the inlet chamber adjacent the sealing member 58 and the outlet openings at that end of the outlet chamber adjacent the sealing member 5|. Those parts of the circumferential wall which lie between the inlet openings and the sealing member 5| and between the outlet openings 59 and the sealing member 58 are closed, that is the wall is not perforated. Therefore, when the rotor rotates in a clockwise direction, Fig. 1, the air is drawn from the inlet chamber through the openings 58 and as each blade passes beyond the inlet openings the air in front of the same is compressed between the circumferential wall of the casing and the rotor and is delivered under pressure to the outlet openings 59. However, the Diesel engine with which this apparatus is to be associated is reversible and it is desirable that the compressor shall function when rotated in either direction by the engine. Therefore, as above stated, the circumferential wall of the casing is adjustable circumferentially and by moving that wall slightly less than a quarter of a revolution the inlet and outlet openings are moved to the positions shown in Fig. 2, where the inlet openings 58 are at that end of the inlet chamber 56 adjacent the sealing member 5| and the outlet openings 59 are at that end of the outlet chamber 55 adjacent the sealing member 50. Consequently when the rotor is rotated in a counter-clockwise direction, in Fig. 2, the air will again be drawn throughthe inlet openings 58 and compressed and delivered through the outlet openings 59 to the air reservoir.

The circumferential wall of the casing may be adjusted in any suitable manner and this may be conveniently accomplished by attaching the ends of a flexible member to the circumferential wall 26 at circumferentially spaced points and providing an actuating device acting on that flexible member and operable from the exterior of the housing to rotate the circumferential wall in one direction or the other. Preferably the flexible member is in the form of a metallic tape 60 having a longitudinal series of perforations BI and extends about a sprocket wheel 62 mounted in the outlet chamber 55 on a shaft 63 which extends through the wall of the crank case and is adapted to be connected with suitable operating mechanism. The operating mechanism is not here shown but it may be of any suitable character and preferably is such that the adjustment of the inlet passages can be effected by the reversing mechanism of the engine.

Sometimes it is desirable that the air entering the compressor shall be filtered to remove solid matter therefrom. This may be conveniently accomplished' by Placing within the dome shaped forward end of the outer housing a suitable filtering material 5.4 which extends across the openings 58a, so that all air entering the housing must pass through this filtering material. In order to retain the filtering material in compact form and to prevent it from entering the inlet -5 for the inlet chamber an inwardly extending flange 65 is interposed between the outer end of the casing and the outer end of the housing.

6I The flange may bev of any suitable width andany suitable quantity of filtering material may be placed in the housing.

In Figs. 9 to 14 there is shown a modified form of the compressor, or blower, in which the cylindrical casing comprises end walls 10 and H and the circumferential wall 12, the walls being rigidly connected one to the other by bolts 13. The casing is supported on the end wall 74 of the crank case of a Diesel engine, and in the present arrangement a frame 15 is mounted in an opening in the wall 74 and rigidly secured to that wall, as by bolts not shown. On that side adjacent the compressor the frame is provided with an annular shoulder 76, and the adjacent wall 10 of the casing is provided with an inwardly facing annular shoulder 11 which fits snugly about the shoulder H5 of the frame, thus supporting the compressor on the frame and centering thev same with relation to the crank shaft of the engine. The frame 15 is provided with a bearing 18 in which is journaled the crank shaft 79 of the engine. This crank shaft has an end portion 80, preferably of reduced diameter, which constitutes the compressor shaft and is rotatably mounted in bearings 8| carried by the casing walls 18 and H and arranged eccentrically with relation to the axis of the casing. The bearings are here shown as cast integral with and extending inwardly beyond the respective walls.

The rotor 82 is mounted on the eccentric shaft 88 for rotation therewith and, in the form shown, comprises a hub portion 83 mounted on the shaft between the bearings 8| and secured thereto by a key 84. Arranged concentric with the shaft in radially spaced relation to the hub is a substantially cylindrical circumferential wall 85 of the rotor, said wall being of an axial length approximating the distance between the end walls of the casing. The circumferential wall and the hub are connected one with the other by substantially radial members 86, which may be called spokes, and which are preferably cast integral therewith. The radial members, or spokes, are arranged to form radial guideways between adjacent spokes and as here shown, they are of approximately sector shape and are of an axial length somewhat less than the length of the hub, the end portions thereof being recessed at 8! to reduce the weight. The opposed radial surfaces of adjacent spokes are substantially parallel for the major portion of their length to form the uideways 88 but are provided adjacent their outer ends with opposed transverse ribs 89 to reduce the width of the guideways. The circumferential wall 85 is provided with slots 90 extending lengthwise thereof for the full length of that wall and arranged in radial alinement with the respective guideways 88, thus dividing the wall into a series of segments, each of which is carried by one of the spokes.

A series of radial blades 9| are slideably mounted in the respective guideways 88 and extend through the slots 98 in the circumferential wall 85 with their outer ends close to but preferably out of actual contact with the circumferential wall 12 of the casing. The blades thus rotate with the rotor and the inner ends thereof are guided in an annular path concentric with the axis of the casing and, therefore, eccentric to the axis of the rotor. Each blade is thus projected progressively varying distances beyond the rotor as the latter rotates, and the blades are of such radial length that the outer ends thereof are maintained in predetermined positions with re- 7 lation to the circumferential wall of the casing throughout the rotation of the rotor.

The outer portions of the blades, which slide in the slots 90, are of an axial width closely approximating the distance between the end walls of the casing, and the ends thereof are close to but preferably out of direct contact with said walls. The inner portion 92 of each blade is of less axial width than the outer portion thereof and is spaced from both lateral edges of the latter. Each blade is provided adjacent its inner end with laterally extending pintles which are mounted in guide members adapted to travel in annular guideways 93 concentric with the axis of the casing. In the present instance the pintles comprise the end portions of a shaft 94 secured to the blade. Preferably, the blade is formed from a strip of sheet metal bent on itself with its central portion extending about and supported on the shaft 94. Opposed portions of the metal strip adjacent the outer end of the blade are spaced one from the other to form a chamber 95, which is adapted to receive and retain an absorbent material 96 impregnated with a lubricant. The side Walls of said chamber are provided with small orifices 91 through which the lubricant may seep in quantities sufficient to lubricate those portions of the blade which slide in the slot in the wall of the rotor, but not in sufficient quantity to permit any appreciable amount thereof to enter the compression chamber between the rotor and the casing. The opposed portions of said strip of metal at the inner and outer ends of said chamber are rigidly connected face to face, as by spot Welding or brasing.

The guide members for the inner ends of the blades comprise rollers 98 which are rotatably mounted on the respective ends of the blade shaft 95 and are movably supported in the annular guideways, there being of course a guideway at each side of the blade. As here shown, each guideway comprises an annular structure 99 of thin material and substantially U-shaped in cross section, thus providing a channel to receive the adjacent rollers 98. The channel is of such radial width that the rollers can rotate freely therein and can revolve about the axis of the casing. Each of said annular structures 99 is supported on an annular ledge or flange I99 which extends inwardly from and is preferably formed integral with the adjacent side wall of the casing. The flange T90 is eccentric to the rotor shaft 8| and is of a diameter substantially greater than the diameter of the adjacent bearing 83, but in the arrangement shown merges into and forms a part of the bearing structure for a portion of the circumference of the latter. Preferably, the annular guideway structure 99 is rotatably supported on the flange lllfl but is mounted in close running contact therewith.

Any suitable means may be provided for lubrieating the contacting surfaces of the flanges and the annular structures, and in the present construction this means is connected with the lubricating means for the rotor shaft 80. The rotor shaft is provided with an axial bore lill which is connected with a suitable source of lubricant supply, not shown, and with radial ducts I92 leading to the shaft bearings 83. Those portions of the flanges Hill which are also parts of the respective bearings are provided with ducts 33 which lead from the bearing surfaces of the latter to the bearing surfaces of the flanges and are arranged in the radial plane of the corresponding ducts in the shaft, so as to receive lubricant therefrom as the rotor rotates. It is important that no lubricant should enter the compression chamber where it would be picked up by the air being compressed. To prevent lubricant from the guideways being thrown by centrifugal force onto the blades and carried into the compression chamber an annular guard I04 extends about each guideway, projects beyond the inner side of the latter and has at its inner edge a radial flange I95, thus causing the lubricant which is thrown against the guard to be directed through the ducts I66 in the end wall of the casing to drain channels lfl'l. The inner circumferential walls of the guideway structures 99 also extend laterally beyond the flanges I00 and are bent inwardly at N28 to deflect any lubricant escaping from the bearing surfaces inwardly and to cause the same to pass to the drain channels.

In the arrangement illustrated the blades are arranged in pairs, the two blades of each pair being in a plane extending through the axis of the rotor, whereby the centrifugal forces on the blades are well balanced. In an arrangement of this kind the outer wall of the rotor may not be truly eccentric to the annular guideways, and in order that the outer edge of each blade may be maintained in the same relation to the circumferential wall of the casing at all times during its rotation, it is desirable that the blade should be capable of a slight radial movement with relation to the guideways. For this purpose the blade supporting rollers may be of such diameter with relation to the guideways that they will have the necessary radial movement therein, this movement being so slight that it does not appear in the drawings, and the rollers are at all times yieldably urged inwardly.

In the present instance an endless or loop shaped spring I09 extends about each pair of opposed blade shafts and across the rotor hub, the latter being provided with grooves lll9a to properly position the springs On each side of the hub the arms of the spring are bent at an angle to cause the same to converge toward the respective blade shafts. The stiffness of the spring is such as to constantly urge the rollers toward the Wall of the guideway but to yield and permit the angular positions thereof to partially straighten, and thus enable the rollers to follow the Variations in their path.

The circumferential wall of the casing 12 is provided in its upper portion with an opening Ill] through which air to be compressed may enter the casing. Preferably the wall 12 at the front end of the opening extends rearwardly in spaced relation to the opening, as shown at III, to form a deflector which will direct the air into the casing. In its lower portion the wall 12 is provided with an outlet opening H2 through which the compressed air is discharged into an air chamber from which it is delivered to the engine casing. In the arrangement shown the wall 12 is provided with downwardly extending parts H3 connected at their lower ends by a bottom wall I I4, and the sides of the chamber are closed by upright walls H5, which form in effect continuations of the end walls of the casing. The side walls I 15 of the air chamber are provided with outlets H6 leading to a channel In, which communicates with the engine casing through an opening H8 in the wall 14. The channel II! is shown as formed in a member H9 separate from and detachably secured to the adjacent side wall H5, as by screws I20. The connection between the member H9 and the wall 14 about the opening H8 is sealed by a continuous sealing member I2l. Both side walls of the chamber are provided with the openings l I 6, and the opening in that wall which is remote from the engine casing is closed by a plate I22 and a sealing member I23. This arrangement permits either end of the compressor casing to be connected with the engine structure by disconnecting the channel member H9 from one wall I I and connecting it with the other wall H5, it being noted that the end wall ll of the casing is also provided with a shoulder 11, so that it can be mounted on the supporting frame 15 when the compressor is turned end for end.

While I have shown and described certain embodiments of my invention I wish it to be understood that I do not desire to be limited to the details thereof as Various modifications may occur to a person skilled in the art.

Having now fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A compressor comprising a shaft, a rotor including a cylindrical body mounted on said shaft for rotation therewith and a plurality of radially movable blades, a cylindrical casing eccentric to said rotor and enclosing the same, a cylindrical housing extending about said casing with its circumferential wall spaced from the circumferential wall of said casing, sealing members in the space between said circumferential walls to divide said space into an inlet chamber andan outlet chamber, the circumferential wall of said casing having openings adjacent one of said sealing members and spaced from the second sealing member to connect the inlet chamber with the interior of said casing, and having openings adjacent said second sealing member and spaced from the first mentioned sealing member to connect the interior of said casing with said outlet chamber, an end wall closing one side of said outlet chamber and having an opening leading into said inlet chamber, and a second end wall closing the other side of said inlet chamber and having an opening leading from said outlet chamber.

2. In a compressor for supplying fluid under pressure to the interior of a structure having a rigid wall, a housing having a circumferential wall secured at one end to and supported by said rigid wall, a shaft extending through said rigid wall into said housing, a cylindrical casing including end walls mounted about said shaft eccentrically thereto and held against rotation therewith and a circumferential wall spaced from the circumferential wall of said housing, a rotor mounted on said shaft for rotation therewith within said casing and having radially movable blades, means for dividing the space between the circumferential walls of said housing and said easing into inlet and outlet chambers, a wall extending inwardly from the circumferential wall of said housing across one side of said space and having an opening communicating with one of said chambers, said rigid wall extending across the other side of said space and having an opening communicating with the other of said chambers, said casing being provided with inlet and outlet openings communicating with the respective chambers.

3. A compressor comprising a shaft, a rotor connected with said shaft for rotation therewith and having a plurality of blades, a cylindrical casing supported about said rotor eccentric to the axis thereof, a structure arranged exteriorly of said casing and having an inlet chamber and an outlet. chamber, said casing having a movable part provided with constantly open fluid passages to connect the respective chambers with the interior of said casing, and means for actuating said movable part to connect predetermined portions of said casing with the respective chambers when said rotor is to rotate in one direction and to connect other predtermined portions of said casing with the respective chambers when said rotor is to rotate in the other direction.

4. Acompressor comprising a shaft, a rotor connected with said shaft for rotation therewith and having a plurality of blades, a cylindrical casing supported about said rotor eccentric to the axis thereof, a cylindrical housing mounted about said casing with its circumferential wall spaced from the circumferential wall of said casing, means for dividing the space between said circumferential walls into an inlet chamber and an outlet chamber, a wall of said casing having fluid passages connecting the interior thereof with the respective chambers, said last named wall being movable to locate said fluid passages adjacent either of the ends of the respective chambers, all of said passages being open in all positions of said movable wall.

5. Acompressor comprising a shaft, a rotor connected with said shaft for rotation therewith and having a plurality of blades, a cylindrical casing supported about said rotor eccentric to the axis thereof and including end walls and a circumferential wall adjustable about the axis thereof, a cylindrical housing mounted about said casing concentric to said shaft with its circumferential wall spaced from the circumferential wall of said casing, sealing members dividing the space between said circumferential walls into an inlet chamber and an outlet chamber, the circumferential wall of said casing having in diametrically opposite portions thereof fluid passages connecting the interior of said casing with the respective chambers at points adjacent the respective sealing members, and means for actuating said circumferential wall of said casing to move the r fluid passage for each chamber from a position adjacent one sealing member to a position adjacent the other sealing member.

6. A compressor comprising a shaft, a rotor connected with said shaft for rotation therewith and having a plurality of blades, a cylindrical casing supported about said rotor eccentric to the axis thereof and including end walls and a circumferential wall adjustable about the axis thereof, a cylindrical housing mounted about said casing concentric to said shaft with its circumferential wall spaced from the circumferential wall of said casing, sealing members dividing the space between said circumferential walls into an inlet chamber and an outlet chamber, the circumferential wall of said casing having in diametrically opposite portions thereof, fluid passages connecting the interior of said casing with the respective chambers at points adjacent the respective sealing members, a flexible member connected at its end with said circumferential wall of said casing, and a device mounted in one of said chambers, operable from the exterior thereof and engaging said flexible member to actuate said circumferential wall of said casing to move the fluid passage for each chamber from a position adjacent one sealing member to a position adjacent the other sealing member.

7. A compressor comprising a shaft, a rotor connected with said shaft for rotation therewith and having a plurality of blades, a cylindrical casing supported about said rotor eccentric to the 11 axis thereof and including-stationary endwalls and a circumferential wall rotatable .with relation to said. end walls, a housing arranged exteriorly of said-casing and having an inletchamber and an outlet chamber, fluid passages in said circumferential wall connecting the respective chambers with the interior of said casing, said passages being open in all positions of saidwall, and means for rotating said wallto locate said passages in predetermined positions with relation to said rotor when said rotor rotates in one direction and in other predetermined positions with relation to said rotor when said rotor rotates in the other direction.

EVERETT P. LARSH.

REFERENCES CITED The following references are of record injhe file of this patent:

Number Number UNITED STATES PATENTS Name Date Hoyt May 29, 1888 Whipple Dec. 29, 1891 Reichhelm Aug. 8, 1893 Young' July 30, 1907 Kutchka Apr. 13, 1920 Olson May 4, 1920 Smith May 11, 1920 Piatt Oct. 11, 1921 Newberg Feb. 5, 1924 Lusso Jan. 8, 1929 Kuhn Oct. 6, 1931 Borsting Jan. 14, 1947 FOREIGN PATENTS Country Date Great Britain June 22, 1867 France July 1'7, 1928 

